a.) Field of the Invention
The invention is directed to a bolt lock for mounting in a thin wall, such as a sheet metal cabinet door, comprising a handle plate which can snap into a rectangular cutout in the thin wall and which has, at one side of the rectangle, a bolt that is supported so as to be displaceable against spring force relative to the thin wall. While the foregoing description and drawings represent the present invention, it will be obvious to those skilled in the art that various changes may be made therein without departing from the true spirit and scope of the present invention.
A bolt lock of this kind is known to the present Applicant from Brochure Sheet G-9 by Southco, U.S.A. A bolt lock of the type mentioned above can snap into a suitably dimensioned opening in a door leaf, whereupon the door or flap can be pushed closed, wherein the bolt engages behind a case or frame to which the door is hinged. When the door or flap is pushed closed, the handle plate is displaced inside of the correspondingly dimensioned right-angled opening in the door leaf against the force of a spring which is articulated at the handle plate and which presses against the edge of the opening, wherein, as a result of the inclined surface of the bolt, this displacing movement is carried out automatically when the door or flap is pushed closed. As soon as the bolt engages behind the case or frame, the spring presses the handle plate in the opposite direction and accordingly locks the door at the door frame.
The known lock is available in different constructions for defined thicknesses, e.g., 1.2 mm, 1.6 mm and 2.2 mm, of the door leaf. Deviations in thickness greater than 0.2 mm are not permissible because the arrangement would then jam or rattle.
Nevertheless, the lock described above has the advantage that it can be mounted in a door leaf without the need for its rear side to be accessible. In other known locks for sheet metal cabinet doors or flaps, mounting requires access to the rear side of the door leaf so that a lock inserted through a corresponding opening in the door leaf from the front can be fastened to the rear side by means of a nut or an attachable spring part.
It is the primary object of the invention to further develop a bolt lock of the type mentioned above in such a way that it does not require a separate series for every thickness of sheet metal, but rather can be adapted to a relatively large range of different sheet metal thicknesses without impeding operation or rattling.
The above object of the invention is met in that the bolt is formed by a second (inner) handle plate which is supported so as to be displaceable against spring force in the first (outer) plate which is held in the thin wall.
As a result of this step, the movability of the plate supporting the bolt is no longer influenced by the sheet metal thickness holding the outer plate; rather, the arrangement can be further developed such that it can be securely fastened in thin walls having a relatively large variation in wall thickness.
In order to fix this first, outer plate in the rectangular opening of the wall such as a door leaf, the plate has, at least at one side wall, a projection which projects beyond the outer wall plane and which can be deflected back against spring force when the plate is pressed into the sheet metal cutout in the wall plane and which forms a projection tip which contacts the inside of the sheet metal wall in a clamping manner when pressed in. As a result of this feature, the plate can snap into the rectangular cutout of the thin wall from the front without the need for the rear side of the thin wall to be accessible. The plate need not be displaceable in the rectangular cutout as in the prior art, so that the plate can be held in the wall by relatively large spring forces and friction coefficients, which benefits the stability of the arrangement.
Due to the fact that the second plate is mounted in the first plate so as to be displaceable against spring force, it is possible to guarantee optimum displaceability by ensuring a support which is extensively free of play, but which has sufficient ability to slide. The second plate, which can be received inside the first plate in a sliding manner, can be exchanged, if necessary, in order to adapt the bolt offset to different thicknesses of the door frame, for example. The outer plate can also be exchanged, if necessary, in case of a large variation in door thickness ranges.
According to a further development of the invention, the first plate can form an opening in the side wall at the side facing the bolt, wherein the second plate with the bolt supported by the second plate projects through this opening in a displaceable manner. The bolt lock can advantageously be arranged in such a way that the first plate forms an edge at the upper end of the side wall remote of the bolt, which edge projects into the inner cavity of the first plate until it forms a rear grip surface for opening the door, or the like, at least when the second plate is pulled back or deflected back into the first plate. In this case, no additional handle need be provided for opening the door (for which purpose, two hands would be required under certain conditions). Rather, the finger used to push back the second plate into the unlocked position, possibly after unlocking displacement, can engage behind this rear grip surface and exert a pulling force for swinging open the door.
According to yet another development of the invention, the first plate forms a cover which projects outward over the side walls of the plate on all sides and rests on the edge of the opening after the plate has been inserted into the opening in the thin wall. The rectangular cutout, which may have sharp edges, is covered by means of this step. The cover preferably has an opening for access to the second plate, this opening being arranged in such a way that it forms the rear grip surface for opening the door, or the like, when the second plate is deflected back.
The two side walls of the first plate which lie opposite one another and advisably form a slide guide for the second plate have two notches which face away from the cover plane vertically and enclose a tongue with a holding surface extending into the vicinity of the lower cover edge surface. In this way, there is a holding projection on both sides of the plate, which benefits the stability of the arrangement.
Alternatively, the side wall of the first plate lying opposite the bolt can also form notches facing away from the cover plane vertically, these notches enclosing a tongue which extends into the vicinity of the lower cover edge surface.
In this case, the fastening is carried out at another location, but one which can likewise ensure adequate stability.
This applies in particular when the first, outer plate at the side facing the bolt forms two shoulders which extend diagonally upward in the direction of the thin wall from the end faces of the two side walls perpendicular to this side and which terminate close to the plane of the thin wall so as to receive the bolt between them in a sliding manner. These shoulders contact the rear surface of the thin wall when the plate is inserted into the cutout at an inclination and thus ensure a secure hold at this location, which results in a highly stable arrangement.
These shoulders can be constructed in a suitable manner so as to be flexible in order to adapt to different sheet metal thicknesses to a determined extent.
Similarly, it is possible to adapt to different sheet metal thicknesses in that the free end of the tongues forms an inclination, which can also be provided with ribs, such that this inclination contacts the lower edge of the opening in the thin wall and accordingly securely locks the plate in the opening even when the thickness of the thin wall varies.
It is advantageous when a pressure spring such as a helical spring is arranged between the outer surface of the wall of the inner plate remote of the bolt and the inner surface of the wall of the outer plate remote of the bolt. In this way, the inner plate is pressed in its locking position, so that the bolt works as a door latch. In order to hold the spring in place, it can be advantageous when a shoulder for receiving one end of the helical spring is provided on the outer surface of the wall of the inner plate remote of the bolt. This shoulder can have a circular shape or can be cross-shaped in cross section, which is advantageous for technical reasons pertaining the injection molding.
The base of the outer plate can have an opening into which a shoulder projecting from the base of the inner plate can extend in such a way that it defines the thrusting or translational movement of the inner plate into the outer plate at least in the direction of the bolt. This prevents the bolt from being completely pressed out of the outer plate through the spring force under certain conditions. This shoulder is advisably ramp-shaped in longitudinal section, the sloping line of the ramp being directed away from the bolt. This means that the two plates can be mounted one inside the other without the need for special handling, but are then locked one inside the other so that they cannot come apart while being transported or when mounting in a door leaf.
The spring which reinforces the latch operation of the bolt can serve at the same time to support the tongue which holds the outer plate inside the thin wall, so as to reduce the risk that its spring force will decrease excessively over the course of time, which can happen in many plastics.
The invention will be explained more fully in the following with reference to embodiment examples shown in the drawings.